The Army's top officer is concerned about a backlash against Muslims in the US military following the shootings at Fort Hood. But, he says, the military's tradition of accepting people from different faiths must never waver.

As investigators sifted through the aftermath of the shootings at the Texas Army base, allegedly carried out by a Muslim Army officer, Gen. George Casey warned against drawing broader conclusions about the Muslim community.

"Frankly, I'm ... concerned that this increased speculation could cause a backlash against some of our Muslim soldiers," Casey, chief of staff of the Army, said on CNN's "State of the Union" program. "As great a tragedy as this was, it would be a shame if our diversity became a casualty as well."

Maj. Nidal Malik Hasan, an Army psychiatrist, is suspected of a shooting rampage at Fort Hood last Thursday in which 13 people were killed and nearly 30 injured. The incident has sparked fear that Hasan was a religious fanatic, once again drawing attention to Muslims in the armed forces. But the overall picture that emerges about their service is hardly one of strife and fundamentalism.

At least 3,500 Muslims are known to be across the military. An additional 283,000 service members have not identified themselves with any religious preference, meaning there could be more Muslims who do not describe themselves that way for military records. Hasan's personnel files did not identify him as Muslim, for example.